/ 
qo Count Rumford's Inquiry concerning 
this air may have had some share in the generation of the heat 
produced ? 
Experiment No. 3. 
A quadrangular oblong deal box, (see fig. 4.) water-tight, 
1 li English inches long, 9 /q inches wide, and 9 t 6 q inches deep, 
(measured in the clear,) being provided, with holes or slits in 
the middle of each of its ends, just large enough to receive, the 
one, the square iron rod to the end of which the blunt steel 
borer was fastened, the other, the small cylindrical neck which 
joined the hollow cylinder to the cannon; when this box (which 
was occasionally closed above, by a wooden cover or lid moving 
on hinges,) was put into its place; that is to say, when, by 
means of the two vertical openings or slits in its two ends, (the 
upper parts of which openings were occasionally closed, by means 
of narrow pieces of wood sliding in vertical grooves,) the box 
(g, b, i, k, fig. 3.) was fixed to the machinery, in such a manner 
that its bottom (z, k,) being in the plane of the horizon, its axis 
coincided with the axis of the hollow metallic cylinder ; it is 
evident, from the description, that the hollow metallic cylinder 
would occupy the middle of the box, without touching it on either 
side, (as it is represented in fig. 3. ;) and that, on pouring water 
into the box, and filling it to the brim, the cylinder would be 
completely covered, and surrounded on every side, by that fluid. 
And farther, as the box was held fast by the strong square iron 
rod, (m,) which passed, in a square hole , in the centre of one of 
its ends, [a, fig. 4.) while the round or cylindrical neck, which 
joined the hollow cylinder to the end of the cannon, could turn 
round freely on its axis in the round hole in the centre of the 
other end of it, it is evident that the machinery could be put 
